Improving the efficiency of the drawover anaesthetic breathing system

Anaesthesia. 2007 Nov;62(11):1171-4. doi: 10.1111/j.1365-2044.2007.05224.x.


We investigated modifications to the reservoir tube usually used in drawover anaesthetic breathing systems as a method of improving its efficiency and performance. The resulting oxygen concentration was recorded at different oxygen flow rates whilst an artificial lung was being ventilated over a range of minute volumes. Addition of a reservoir bag and valves significantly increased the measured percentage of oxygen at the common gas outlet when compared to a 300-ml reservoir tube. There was no difference in the percentage of oxygen when comparing a reservoir bag and a 600-ml reservoir tube.

MeSH terms

  • Anesthesia, Inhalation / instrumentation*
  • Drug Administration Schedule
  • Equipment Design
  • Humans
  • Oxygen / administration & dosage
  • Respiration, Artificial


  • Oxygen